Thread sensing arrangement

ABSTRACT

A thread sensing arrangement for controlling the stop motion of a textile machine has a sensing means which turns about an axis located on an imaginary straight line through the path of the thread, and extending substantially in the direction in which the thread is supplied to the path which is formed by a pair of guide means mounted for angular movement about an other axis located on an other imaginary straight line through the path which defines an acute angle with the direction in which the thread is supplied to the guide means.

United States Patent Frei [ 51 Sept. 12, 19,72

[54] THREAD SENSING ARRANGEMENT 72 Inventor: KarlFrei, Morickestr.9,7477 Onstmettingen, Germany [22] Filed: Jan. 16, 1970 [21] Appl. No.: 3,385

[30] Foreign Application PriorityData Jan. 23, 1969 Germany ..P 19 03 195.9 9

Sept. 17, 1969 Germany ..G 69 36 384.4

Nov. 7, 1969 Germany ..G 69 43 236.6

[52] U.S. Cl ..28/l R, 28/51, 66/157 [51] Int. Cl. ..D04b 35/14 [58] Field of Search ..28/1, 51; 66/157, 158, 163 I [56] References Cited UNITED STATES PATENTS 2,700,880 2/1955 Horne ..66/l63 2,711,093 6/1955 Edelmanetal, ..66/l63 2,785,559 3/1957 Davis et a1. ..28/5l X 2,952,890 9/ 1 960 Stanier ..28/5l 2,963,890 1 12/1960 Hoots ..66/157 3,429,146 2/1969 Crach ..66/ l 63 3,482,420 12/1969 Bourgeois ..66/ l 58 Primary Examiner Louis K. Rimrodt Attorney-Michael S. Striker [57] ABSTRACT A thread sensing arrangement for controlling the stop motion of a textile machine has a sensing means which turns about an axis located on an imaginary straight line through the path of the thread, and extending substantially in the direction in which the thread is supplied to the path which is formed by a pair of guide means mounted for angular movement about an other axis located on an other imaginary straight line through the path which defines an acute angle with the direction in which the thread is supplied to the guide means.

20 Claims, 5 Drawing Figures PATENTEDsEP 12 m2 3.689 .9653

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INVENTOR KA ru. F2 1' ATTORNEY i r i INVENTOR ATTORNEY PATENTEU 3E? 12 I972 3,689,963

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sum u or 4 Fig- 4 W 10 f. Q6 1'' il\ I INVENTOR 1 THREAD SENSING ARRANGEMENT BACKGROUND OF THE INVENTION The present invention relates to a sensing arrangement controlling the stop motion of a textile machine, such as a circular knitting machine, and is of the type including a pivotally mounted guide means having two guide arms for guiding the thread, and a pivotally mounted sensing means which senses the thread guided by the guide arms. When the tension of the thread becomes too great, the guide means is angularly displaced, and when the thread breaks, the sensing means responds and turns to a position indicating the thread breakage. When either the guide means or the sensing means responds, electric contact means are operated by which the respective machine is stopped with the intermediary of a relay.

In accordance with the prior art, the guide means has two arms turnable about an axis which are held by a spring in a normal operative position in which the arms abut a stop means. The thread is guided on the guide anns. The sensing means also has two arms which are disposed between the guide arms. In the construction of the prior art, the turning movement of the guide arms and the turning movement of the sensing means takes place substantially in the direction in which the thread is supplied to the guide arms and transported away from the same.

Particularly synthetic threads are very elastic, so that they are tensioned while being fed to the machine, and suddenly contract when released by a bobbin. The sudden expansions and contractions of the thread cause oscillations of the sensing means, and also of the guide arms, which have an obstructing and braking influence on the thread. The magnitude of the oscillations and jerks, may cause the formation of loops in the thread, depending on the varying elasticity of the used threads. If the oscillations of the thread unwound from a spool are close to the self oscillation frequency of the oscillating mass, resonance oscillations take place which may effect the actuating of the stop motion of the machine due to extreme oscillating movements of the sensing means, although no thread breakage has occurred.

It is one object of the invention to provide a thread sensing arrangement for the stop motion ofa textile machine which overcomes the disadvantages of prior art constructions serving the same purpose, and assures a quiet working of guide means and of the sensing means without oscillations.

Another object of the invention is to provide the thread sensing arrangement with adjusting means for adaptation to different operational conditions.

SUMMARY OF THE INVENTION With these objects in view, the turning axis of the sensing means is arranged in an extension of the direction in which the thread is supplied and transported away, respectively.

Due to this arrangement according to the invention, the sensing means rests quietly on the thread during operation, and loop formations in the threads, or oscil- ,lations due to irregular thread transport are avoided.

Preferably, the connecting line between the axis of the guide means and the resting points of the thread in the guide portions of the guide arms, forms an acute angle to the direction in which the thread is supplied and transported away, so that the force required for turning the spring-loaded guide means, has a descending characteristic.

The sensing means is advantageously constructed as an angular lever provided with an adjustable weight for varying the force at which the thread is engaged. It is advantageous to construct a sensing means in such a manner that it can easily be exchanged, and also turned out of the region of the thread and arrested.

It is particularly advantageous to bias the guide means with a spring so that when the guide means is displaced by the tensioned thread, the spring is moved beyond a dead center position, and rapidly turns the guide means to a position in which the thread is easily released by the guide means.

It has been found that the texture and elasticity of the used natural and synthetic threads are very variable so that oscillations, and loop formation, takes place to a different degree, frequency and intensity for different threads and different thread tensions. In order to avoid faults in the knitted fabric, it is desirable that the thread is thrown off the guide means when oscillations or loop formation occurs so that the machine is stopped. On the other hand, it is not desirable that the thread is thrown off when a very small oscillation occurs, since this would cause unnecessary stopping of the machine. Consequently, in accordance with another feature of the invention, the dead center position of the spring of the guide means can be adjusted in accordance with the thread type used, and its elasticity. It is particularly advantageous to adjust the dead center position by an eccentric pin on a manually operated knob which acts on the spring to vary the direction in which it acts on the guide means.

i In accordance with another feature of the invention,

the sensing means has a shaft portion on which a heavy disc is loosely mounted for free rotation. Due to the friction between the disc and the shaft portion of the sensing means, oscillations of the sensing means with the shaft portions are suppressed and dampened.

One embodiment of the invention comprises guide means for guiding a thread in one direction to a path, and along the same; sensing means for engaging the thread in the path; and support means supporting the sensing means for angular movement about an axis located on an imaginary straight line through the path and extending substantially in said direction, a deviation of 30 being permissible. In the preferred embodiment, the guide means are also mounted for angular movement about an other axis located on another imaginary straight line through the path and defining an acute angle with said direction. The angle is preferably between 40 and 60.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a rear view of an apparatus according to the invention, the rear wall being omitted for the sake of clarity;

FIG. 2 is a sectional view taken along line II-II in FIG. 1;

FIG. 3 is an elevation, partially in section, as viewed from the right of FIG. 1;

FIG. 4 is a fragmentary rear view, partially in section, illustrating a modification of the apparatus shown in FIGS. 1 to 4, partially corresponding to the section of FIG. 2; and

FIG. Sis a fragmentary rear view of the modified embodiment shown in FIG. 4, the rear wall being omitted for the sake of clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1 to 3 the apparatus has a housing 12 which is preferably made of a transparent or translucent synthetic material which may be dyed red, for example. The housing is secured by means of slotted lugs 14 or clamping screws to a wall of a textile machine whose stop motion is controlled by the apparatus.

Housing 12 has a cover 16 forming its rear wall which is secured by screws or the like to the main portion of the housing 12. A front wall 18 has a recessed portion 20 with an inner projection 22 provided with a threaded bore into which a screw 24 is threaded. Screw 24 has a central bore in which a journal portion 26 has a free end projecting beyond the head of the hollow screw to which a member 30 is secured by means of a screw 31. An attaching pin 32 is secured to member 30 in an eccentric position. One end of a coil spring 34 is secured to the attaching pin 32, and the other end is attached to a plate 36 which is mounted in the housing for movement along guideways 52 and 54 toward and away from attaching pin 32 so that the tension of the spring can be adjusted. Plate 36 is provided with a central threaded bore into which a screw 50 is threaded. Screw 50 passes through a hollow screw 60 which has an inner thread engaging screw 50, and an outer thread threaded into a threaded bore in the wall 58 of housing 12. Screw 60 projects from the inner surface of wall 58 and is secured by a nut 62. When head 63 of screw 50 is turned, screw 50 moves in axial direction and moves plate 36 also in axial direction, since plate 36 cannot turn since its ends are guided in guideways 52 and 54. By turning the serrated head 63, the tension of spring 34 can be adjusted.

Journal portion 26 has a head 29 with an annular recess 38 in which the ends 40 of three guide arms 42 are secured, for example by a press fit, so that the three guide arms 42 are connected with head 29 and journal portion 26, forming with the same a guide means for a thread turnable about the axis defined by screw 24 and journal portion 26. The three ends of guide arms 42 are formed as hooks 44 on which U-shaped members 46 are mounted. As shown in FIG. 1, one leg of each U- shaped member 46 is shorter than the other, so that the ends of each U-shaped member 46 simultaneously abut the outer surface of a slanted wall 100 when the guide means 26, 29, 40, 44, 46 is turned in counterclockwise direction, and viewed in FIG. 1, by spring 34 acting on the eccentric attaching pin 32. The Ushaped members 46 are made of a hard ceramic material, for guiding a thread along a straight path indicated at 80 in FIG. 1.

The thread is supplied in the direction of the arrow A by a guide 110 to the path 80, and moved away in the same direction. As clearly shown in FIG. 1, an imaginary straight line connecting the axis of the guide means, formed by journal 26, and the path in guide members 46, forms an acute angle to the direction A in which the thread is supplied to the guide members 46 through the guide 110.

When the thread tension becomes too high, guide members 46 are pulled downward so that the guide means turns about the axis of journal 26, 28, while the guide members and the thread portion guided by the same, move along a circular path. The force produced by the tensioned thread, and turning the guide means about the axis of journal 26, 28 has a falling characteristic, which means that the force is gradually diminished the farther guide members 46 with the thread portion thereon move away from the normal position shown in FIG. 1 abutting wall 100. This is due to the fact that the effective lever arm of the guide means becomes greater, while the effective lever arm of attaching pin 32 and spring 34 becomes smaller.

When guide means 26, 28, 40, 44, 46 has turned so far that attaching pin 32 moves beyond a dead center position in which attaching pin 32, and spring 34 are aligned with the axis of journal portion 26, 28, spring 34 no longer biasses the guide means to return to the position of FIG. 1, but rapidly turns the guide means in clockwise direction as viewed in FIG. 1 to a position, not shown, in which the slots of guide member 46 point downwardly so that the thread portion along the path 80 is released by the guide means and slides out of guide members 46.

The thread forms a U-shaped loop including the portion along the arrow A, where the thread is guided by the guide 110, the portion on the path 80 guidedby members 46, and another portion parallel to the direction A guided by another guide 1 10, and such loop is necessary to prevent a breakage of the thread since the machine cannot be momentarily stopped.

An imaginary straight line connecting the axis of the guide means, formed by journal portion 26, 28, with the path 80 formed by the thread portion guided by the guide members 46, defines with the feeding direction A I of the thread, and with the corresponding parallel direction in which the thread is transported away from the last guide member 46, determined by guides 110, an angle which is within the range between 30 and 60, without being limited to this range. Preferably, the angle is 40. The direction C in which guide members 46 move, which is perpendicular to a line connecting the axis of the guide means with the path 80, consequently forms in the normal illustrated operational condition with the direction A an angle between 60 and 30, which is preferably 45.

In apparatus according to the prior art, the direction of movement of the guide members coincides with the direction in which the thread is supplied and moved away from the guide members. Due to the arrangement of the invention and the provision of the above explained angles determining the position of theguide means in relation to the direction in which the thread is supplied and transported away, a dampening of the oscillations caused in the apparatus of the prior art due to the irregular running of synthetic threads is obtained.

I projection 64, see FIG. 3, which has a central threaded bore extending through wall 18 into which a screw 66 is threaded whose end 67 project a little from the outer surface of wall 18. Screw 66 has a central bearing bore through which a journal portion 70 of a U-shaped member 71 extends. Journal portion 70 and U-shaped member 71 are part of a sensing means 69. The end'of journal portion 70 projects beyond the head 68 of screw 66, and carries a cam disc 72 which is secured by a screw 73.- The sensing means 69 can turn about the axis defined by journal portion 70. The U-shaped member 72 includes, in addition to the journal portion 70, a connecting portion 74, and a portion'76 which carries two feelerarms'78 attached thereto by soldering, welding, or any, other suitable manner. 7

- The feeler arms 78 are. arranged in the spaces between guide members 46 and have bent free ends 79 abutting the surface of housing wall 100. Feeler arms 78 form a right angle with the connecting portion 74. However, this angle may be smaller or larger than a right angle and is preferably within the range between 60 and 15.03. Connecting portion 74 may have an extension on which a weight, not shown, is slidably mounted for biassing the sensing means 69 to turn in counterclockwise direction as viewed in FIG. l into a butment with the thread portion at 80. By adjusting the position of the weight, not shown, the force exerted by sensing means 69 on the thread can be varied. A similar arrangement is shown in the embodiment of FIG. 4 in which a weight 186 is fixed to the sensing means 69.

In accordance with the invention, the axis defined by journal portion 70 is disposed on an imaginary straight linepassing in the direction A through the point 80, or more accurately, the axis of sensing means 69 is located in a plane passing through the path of the thread at 80 in the direction A in which the thread is supplied to the path 80. The angle between the axis of sensing means 69 and the point 80 of guide member 46 on which the thread rests, may form an angle of plus or minus 30 with the direction A in which the thread is supplied to the guide members 46, without detrimental influence on the advantages obtained by the arrangement. As shown in FIG. 1, the direction indicated by the arrow B in which feeler portion 76 moves about the axis 70 of the sensing means is perpendicular to the direction indicated by the arrow A at the point 80. When the thread portion along the path defined by the point 80 comes loose or breaks, or when the guide arms 42 are turned downward due to increased thread tension, the feeler portion 78 moves in the working direction indicated by the arrow B about journal portion 70. The direction B is perpendicular to a straight line .connect ing the center of journal portion 70 with the point 80, or perpendicular to a plane passing through the axis of journal portion 70 and the path of the thread portion supported by guide members 46.

When the guide means 26, 28, 42, 44, 46 turns about the axis of journal portion 26, 28, points 80 of the three guide members46 move in the direction indicated by the arrow C which forms with the working direction B of the sensing means 69 an angle approximately between 60 and In known apparatus serving the same purpose, the working directions of the sensing means and guide means coincides substantially, which favors the development of oscillations due to resonance and feedback phenomena. In accordance with the invention, these disadvantagesare avoided by providing separate axis for the sensing means and the guide means permitting the sensing means and guide mean to move in different working directions B and C.

A lamp 86 is mounted in the interior of housing 12 by means of a socket 88 covered with a cap 90 consisting of insulating material. Contacts 92, 94 and 92a and 94a are mounted on contact springs 98 which are supported by holding members 96 on wall 100. Contacts 92 and 94 are operated by the cam disc 72 of the sensing means 69, while contacts 920 and 94a are operated by the guide arms 42 by means, of cam disc 30 which turns with journal portion 26, 28 to the position shown in chain lines in FIG. 1 when the thread portion in path 80 breaks. Contacts 92 and 92a effect theconnection and disconnection of lamp 86 from the voltage source, while switch contacts 94 and 940 are part of a stop motion device, and control a relay, not shown, which operates the stop switch of the stop motion of the textile machine when sensing means 69 can turn about the axis ofjournal 70 due to breaking of the thread portion in path 80, and cam 72 assumes the position shown in chain lines in FIG. 1. The electric circuit for this purpose is well known, and since it is not an object of the invention, is not illustrated, excepting connectors 84.

Wall 100 is provided with a layer 48 of a dampening material which dampens'the impacts of guide arms 42 and of the end portions 79 of the sensing means 69 on wall 100. Such impacts occur when the guide arms 42 are urged downward due to increased thread tension, and are then suddenly released by slackened thread before attaching pin 32 has moved beyond its dead center position so that spring 34 can turn the guide means farther in clockwise direction. If the thread is first tensioned and then slackened before the dead center position is reached, spring 34 rapidly turns the guide means in counterclockwise direction until the ends of guide members 46 abut wall 100. Such blows may cause oscillations which are prevented by the dampening layer 48.

As shown in FIG. 3, the wall 100, 48 is provided with a rib 82, which may be integral with the housing, and limits lateral movement of the thread supplied to the first guide member 46 on the left as viewed in FIG. 3. Since the lamp 86 is disposed within the transparent or translucent housing, the entire housing is illuminated when a disturbance takes place, so that the operator can immediately find the sensing apparatus requiring his attention.

FIGS. 4 and 5 illustrate the modified embodiment of the invention which generally corresponds to the embodiment described with reference to FIGS. 1 to 3, but is provided with means by which the dead center position of the guide means 26, 28, 30, 42, 46 can be adjusted.

Guide arms 42, 46 are turned in clockwise direction against the force of spring 34 by a thread whose tension is increased, so that attaching pin 32 also turns about journal 26, 28. As explained above, spring 34 resists clockwise movement of the guide arms 42 until attaching pin 32 has moved beyond the dead center position in which the axis of spring 34 passes through the axis of journal portion 26, 28. Beyond the dead center position, spring 34 does not urge the guide arm 32 back to the normal position shown in FIG. 1, but turns the guide arms 42 rapidly in clockwise direction to release the guided thread.

In the embodiment of FIGS. 4 and 5, the cover 16 has an opening in which an adjusting knob 144, which may consist of synthetic material, is mounted for tuming movement. An adjusting member 146 having a projecting pin 160 is secured to knob 144 by a screw 145 threaded into the inner thread of a tubular sleeve molded together with knob 144. Knob 144 has an annular groove'152 in which a springy ring 154 is inserted so that knob 144 resiliently abuts the outer surface of cover 16 when screw 145 is tightened. Knob 144 has in its outer surface a slot 148 adapted for insertion of a coin by which knob 144 is turned together with member 146 and the eccentric pin 160. Coupling pins 159 are mounted in cylindrical bores 158 of disc member 146 and are fixedly secured to the knob 144 so that a positive coupling between knob 144 and member 146 is obtained. I

When knob 144 is turned, pin 160 moves along a circular path into engagement with the spring 34 which otherwise extends along a straight line between the attaching point; on plate 36 and pin 32, as best seen in FIG. 2.'As shown in FIG. 5, the spring 34 is displaced so that particularlytheend portion adjacent attaching pin 32 extends in a different direction so thatdirection of the spring force acting on the eccentric attaching pin 32 is adjusted. In the new position of the spring, the dead center position of the attaching pin 32 is displaced as compared with the position shown in FIG. 1 so that also the dead center position of the guide arms 42, 46 is adjusted. The new dead center position is reached the sooner, the farther knob 144 is turned in counterclockwise direction as viewed in FIG. 5 since spring 34 is moved farther to the left as viewed in FIG. 5 by the pin 160 when knob 144 is farther turned in counterclockwise direction.

The inner surface of cover 16 may be provided with stops, not shown, engaged by disc member 146 or by pin 160 in two end positions of the knob 144.

In the embodiment of FIGS. 4 and 5, a weight 186 is secured to sensing means 69 and urges the same into engagement with the thread portion guided along the path 80 by guide members 46.

As shown in FIG. 3, the journal portion 70 of the sensing means 69 has an extension 190 carrying a shaft portion 192 whose diameter is Slightly smaller than the diameter of the extension 190. A disc 194 is mounted on shaft portion 192 for free rotation, and is prevented from axial movement by extension 190 and a ring 196. The central bore of disc 194 has a diameter which is greater than the diameter of shaft portion 192 so that disc 1 94 rides on shaft portion 192. Due to its mass and inertia, disc 194 has the tendency to resist the friction torque applied by shaft portion 192 when the sensing lations of sensing means 69 due to its inertia. The friction between disc 194 and shaft portion 192 absorbs very small angular oscillations of sensing means 69 so that no resonance oscillations can develop in the same. 7

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of stop motion arrangements for textile machines differing from the those described above.

While the invention I has been illustrated and described as embodied in a thread sensing arrangement in which guide means and sensing means for a thread are mounted for turning movement about different axes, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

I claim:

1. Thread sensing arrangement, comprising, in combination,

guide means including means forming a guideway for guiding a thread along a path, and means for guiding the thread in one direction to said guideway and path; sensing means having a first position .engaging the thread portion in said guideway and path, and moving to a second position when sensing no thread portion in said path, and being in said second position adapted to actuate a stopv motion switch; r and supporting means including means supporting said sensing means for angular movement about an axis located in a plane which extends in said one direction through said guideway and path.

2. Thread sensing arrangement as claimed in claim 1 wherein said plane and the portion of said thread supplied in said direction to said guideway and path define an angle of less than about 30.

3. Thread sensing arrangement as claimed in claim 1 wherein said path and said axis are parallel.

4. Thread sensing arrangement as claimed in claim 1 and comprising other supporting means supporting said guide means for angular movement about an other axis located in an other plane through said path defining an acute angle with Said one direction.

5. Thread sensing arrangement as claimed in claim 4 wherein said angle is between 40 and 60.

6. Thread sensing arrangement as claimed in claim 1 wherein said sensing means includes an angular lever having feeler means located in said path.

7. Thread sensing arrangement as claimed in claim 6 wherein said angular lever includes a connecting portion transverse to said axis of said sensing means and at least one feeler portion located in said path and defining with said connecting portion an angle of about 8. Thread sensing arrangement as claimed in claim 7 wherein said feeler portion has a free bent end; and comprising a housing having a wall on which said free end of said feeler portion abuts.

9. Thread sensing arrangement as claimed in claim 1 wherein said support means support said sensing means for removal and insertion so that said sensing means can be replaced.

10. Thread sensing arrangement as claimed in claim 1 wherein said sensing means includes a sensing lever and a weight mounted for adjusting movement on said sensing lever for adjustably biassing said sensing means toward the thread in said path and guideway.

11. Thread sensing arrangement as claimed in claim 1 comprising other support means for supporting said guide means for angular movement about an other axis located in another plane through said path and defining an acute angle with said one direction; and wherein said guide means and said sensing means have portions for engaging the thread in said guideway and path, said portions moving about the respective axes in two directions defining an angle between 60 and 70.

12. Thread sensing arrangement as claimed in claim 1 comprising other support means for supporting said guide means for angular movement about an other axis located in another plane through said guideway and path and defining an acute angle with said one direction; wherein said guide means includes a journal means mounted on said other support means, said journal means having an attaching means eccentric to said axis; a spring having one end secured to said eccentric attaching means for urging said guide means to turn in one direction to a normal position for guiding the thread along said path whereby when the thread is tensioned and turns said guide means in the opposite direction about said other axis, said one end of said spring moves through a dead center position in which said one end is aligned with said other axis, to'a position biassing said guide means to turn rapidly farther in said opposite direction to a position in which said guide means releases the thread.

13. Thread sensing arrangement as claimed in claim 12 including adjusting means for varying the position of said spring and thereby said dead center position.

14. Thread sensing arrangement as claimed in .claim 13 wherein said adjusting means include a turnable member having an eccentric part engaging said spring so that the same is deflected when said member is turned, and acts on said journal means in a different direction.

15. Thread sensing arrangement as claimed in claim 14 wherein said adjusting means include a knob connected with said member for turning movement; and stop means limiting turning movement of said member in two end positions.

16. Thread sensing arrangement as claimed in claim 1 and comprising a housing formed with outer ribs for limiting lateral movements of the thread along said path.

17. Thread sensing arrangement as claimed in claim 1 comprising a housing having a wall for limiting movement of said sensing means; and including a layer on said wall consisting of a damping material.

18. Thread sensing arrangement as claimed in claim 1 wherein said sensing means infludes a shaft portion mounted on said support means or turning movement about said axis; and comprising a disc mounted for free turning movement on said shaft portion whereby oscillations of said sensing means are dampened.

19. Thread sensing arrangement as claimed in claim 18 wherein said shaft portion has a predetermined diameter; wherein said disc has a central bore having a greater diameter than said predetermined diameter; and wherein said shaft portion passes through said bore.

20. Thread sensing arrangement as claimed in claim 19 wherein the mass of said disc is substantially greater than the mass of said sensing means. 

1. Thread sensing arrangement, comprising, in combination, guide means including means forming a guideway for guiding a thread along a path, and means for guiding the thread in one direction to said guideway and path; sensing means having a first position engaging the thread portion in said guideway and path, and moving to a second position when sensing no thread portion in said path, and being in said second position adapted to actuate a stop motion switch; and supporting means including means supporting said sensing means for angular movement about an axis located in a plane which extends in said one direction through said guideway and path.
 2. Thread sensing arrangement as claimed in claim 1 wherein said plane and the portion of said thread supplied in said direction to said guideway and path define an angle of less than about 30*.
 3. Thread sensing arrangement as claimed in claim 1 wherein said path and said axis are parallel.
 4. Thread sensing arrangement as claimed in claim 1 and comprising other supporting means supporting said guide means for angular movement about an other axis located in an other plane through said path defining an acute angle with said one direction.
 5. Thread sensing arrangement as claimed in claim 4 wherein said angle is between 40* and 60*.
 6. Thread sensing arrangement as claimed in claim 1 wherein said sensing means includes an angular lever having feeler means located in said path.
 7. Thread sensing arrangement as claimed in claim 6 wherein said angular lever includes a connecting portion transverse to said axis of said sensing means and at least one feeler portion located in said path and defining with said connecting portion an angle of about 90*.
 8. Thread sensing arrangement as claimed in claim 7 wherein said feeler portion haS a free bent end; and comprising a housing having a wall on which said free end of said feeler portion abuts.
 9. Thread sensing arrangement as claimed in claim 1 wherein said support means support said sensing means for removal and insertion so that said sensing means can be replaced.
 10. Thread sensing arrangement as claimed in claim 1 wherein said sensing means includes a sensing lever and a weight mounted for adjusting movement on said sensing lever for adjustably biassing said sensing means toward the thread in said path and guideway.
 11. Thread sensing arrangement as claimed in claim 1 comprising other support means for supporting said guide means for angular movement about an other axis located in another plane through said path and defining an acute angle with said one direction; and wherein said guide means and said sensing means have portions for engaging the thread in said guideway and path, said portions moving about the respective axes in two directions defining an angle between 60* and 70*.
 12. Thread sensing arrangement as claimed in claim 1 comprising other support means for supporting said guide means for angular movement about an other axis located in another plane through said guideway and path and defining an acute angle with said one direction; wherein said guide means includes a journal means mounted on said other support means, said journal means having an attaching means eccentric to said axis; a spring having one end secured to said eccentric attaching means for urging said guide means to turn in one direction to a normal position for guiding the thread along said path whereby when the thread is tensioned and turns said guide means in the opposite direction about said other axis, said one end of said spring moves through a dead center position in which said one end is aligned with said other axis, to a position biassing said guide means to turn rapidly farther in said opposite direction to a position in which said guide means releases the thread.
 13. Thread sensing arrangement as claimed in claim 12 including adjusting means for varying the position of said spring and thereby said dead center position.
 14. Thread sensing arrangement as claimed in claim 13 wherein said adjusting means include a turnable member having an eccentric part engaging said spring so that the same is deflected when said member is turned, and acts on said journal means in a different direction.
 15. Thread sensing arrangement as claimed in claim 14 wherein said adjusting means include a knob connected with said member for turning movement; and stop means limiting turning movement of said member in two end positions.
 16. Thread sensing arrangement as claimed in claim 1 and comprising a housing formed with outer ribs for limiting lateral movements of the thread along said path.
 17. Thread sensing arrangement as claimed in claim 1 comprising a housing having a wall for limiting movement of said sensing means; and including a layer on said wall consisting of a damping material.
 18. Thread sensing arrangement as claimed in claim 1 wherein said sensing means includes a shaft portion mounted on said support means for turning movement about said axis; and comprising a disc mounted for free turning movement on said shaft portion whereby oscillations of said sensing means are dampened.
 19. Thread sensing arrangement as claimed in claim 18 wherein said shaft portion has a predetermined diameter; wherein said disc has a central bore having a greater diameter than said predetermined diameter; and wherein said shaft portion passes through said bore.
 20. Thread sensing arrangement as claimed in claim 19 wherein the mass of said disc is substantially greater than the mass of said sensing means. 